Due to the growing trend of vehicle electrification and demands for improved mechanical
efficiency, modern formulated lubricants must meet various more stringent
requirements. Using a multifunctional tribometer, a conventional transmission oil for
internal combustion engine vehicles was compared with specific transmission fluids designed
for hybrid and electric vehicles. Through tribological testing under the influence
of an electric field, friction and wear data were acquired, after which correlations were
established between the obtained results, lubricant properties, and electrical current.
It was found that the electric current significantly affects the lubrication of the contact
and its tribological properties. Due to the extremely small contact area, a very high
electrical current density is present, which has a destructive effect on wear—particularly
at low operating speeds within the boundary lubrication regime. Despite the significantly
lower viscosities of the formulated lubricants, the properties of the base oils and
specialized additives enable comparable control over friction and wear rate, while maintaining
the most uniform surface wear, even in the least favorable boundary lubrication
regime.
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